David Williams} Is Simon Gay?"Look at how erect his nipples are"

Amanda Holden revealed yesterday that David Walliams has had everyone on Britain's Got Talent cringing with his close to the mark sense of humour.

But earlier this week the comedian took things too far while recording an interview on The Jonathan Ross show.

Walliams left the music mogul fuming after making regular jokes about his sexuality, pushing Cowell to the limit.

Not a happy bunny: Simon Cowell appeared to be struggling as he posed up with David Walliams on the Jonathan Ross show, where the comedian left the mogul fuming with his jokes about his sexuality

The controversy began when Walliams, promoting Britain's Got Talent, told Jonathan: 'The main question I get is, "Is Simon gay?" Even my mum asks. She says, "He's nice. Is he gay?" '

And while Cowell attempted to bring the conversation back around to work, saying that he often worked from midday to 5am, Walliams joked: 'At 12 o'clock at night you're working quite hard - because that's when the ladyboys come round.'

Cowell, apparently finding the jokes a bit close to the mark, said: 'It's worth pointing out that I have a relationship with ITV and most of this will be edited out.'

The BGT boss was then apparently overheard telling Ross as the show broke for an advert segment: 'I want to have a word with you.'

However, despite things beginning professionally enough after the advert break, Walliams was quick to return to his naughty jokes, showing Ross a picture of himself and Simon on his phone.

He told the presenter: 'This proves that Simon does like me. Look at how erect his nipples are!'

However, a source close to Simon said he took it all in good humour, adding: 'Simon knows exactly what David & Jonathan are like!'

And Cowell even joked on his Twitter page last night: 'Did Jonathan Ross show last night with @davidwalliams - he's out of control. Just wait till BGT starts David, I'll get my own back!'

Walliams then replied: 'Honey, I am just getting started! You wait until the live shows!'